mxmx serve

It's been a while that I've been here...and I finally got the chance to take some footage of my serve as some may have suggested I do...

The balls were extremely flat and smooth, so much so that I struggled to even control the bounce - but it is footage nonetheless. I would really need to make plan to do this again with newer balls. Anyways...scary how much slower ball movement actually appears on camera. I guess the pro's really must strike the ball well :shock: Would like to hear any feedback guys

Not bad.
I'd take more time between each serve, since you HAVE the time, to concentrate on storing up the energy, and then hit the ball. Don't just go thru the motions when you serve.
Maybe more sideways.

When Cheetah's advice is on picking up balls, you know you're doing something right

But in all seriousness, two things that stand out to me/you might want to try:

1. Turn your shoulders more when loading up to the trophy pose
2. If you crank it up, you may end up hitting yourself in the leg; f you're hitting a kick serve, follow through more to the right of your body, and if slice/flat, more to the left. Either way, you'll avoid your legs :wink:

That being said, I really like how fluid and easy it looks, and you seem to get a lot of power from it, not to mention that you seem to know where you want to place it. Very nice serve!

I'm not exactly sure what's going on, but your racquet seems to stop before it completes the arc that a follow through generally follows, and you slow the racquet down a lot here. You should have the mindset of keeping the racquet going and continuing through the swing, speeding through contact and not consciously slowing the racquet after you hit the ball

The racket should be to your side, on the left, when you're finished with the swing. Right now, it's in front of you. That means you have to consciously slow down the swing in order to not hit yourself

You have some good advice above already. But adding in the greater shoulder rotation will take a long time to get the timing down.

What I would recommend you working on first is the following:

1. Get a more agressive shoulder angle by getting your tossing arm up straighter.

In pic 1, Pete has his shoulder angle so steep that his tossing shoulder is straight up, and his hitting shoulder is straight down.
[Note that over the hitting his sequence in pic 10, he will end up with his hitting shoulder straight up, and his tossing shoulder is straight down. That reversal takes his arm through a longer distance, giving more time to build up speed.]

2. Don't drop your tossing arm too soon - it looks like you are letting your tossing arm drift down too early.
If you let your tossing arm start to drift down to early, you will lose that steep shoulder angle I recommend above.

Look how long Pete's tossing arm stays straight up in the above photos from pic 3- pic 9 while he is increasing his knee bend and forming more of a bow shape to get into his optimum trophy position to exlplode from.

3. Get a little more lean back of the upper body. See pics 3-9 above. As you have your tossing arm up and are then bending your knees and getting into more of a bow shape, bend back FROM THE KNEES WITH YOUR HEELS OFF THE COURT (not by arching your back) to get more of the lean back you see Pete gets by pic 9 in his trophy position.
[This will not only help your swing, but help prevent a shoulder injury from opening up the shoulder angle, with less impingement on the most superior of the rotator cuff tendons (supraspinatus).]

As you do this, you will notice you've got to change the angle of your racquet so it appears that you are not hitting with as straight an arm through racquet angle as you currently do.

But that means you will have a better pronation movement - with the increased power that a more powerful pronation will give you.

You can see this appearance of the racquet looking at more of an angle to the hand at ball impact in pic 19 above. But notice in the preceeding pics how the racquet/arm can be pronated through a greater distance for more power, plus the greater low to high motion for more spin.

4. "You've got to drop the left shoulder" - Jim McLennanhttp://www.youtube.com/watch?v=lTRvxaBMh8s
In this video, Jim emphasizes that getting great shoulder over shoulder action is good for your shoulder - there is no pinching of the rotator cuff.

But this is also the way to fully utilize your upper body movement for maximal power and spin.

Look at that first sequence of the Sampras serve above. In pic 1 his tossing shoulder is straight up and his hitting shoulder is straight down.
His shoulder angle totally reverses in the next sequences, so that at ball strike (pic 7) his hitting shoulder is straight up and his tossing shoulder is straight down.

Again, I think you can incorporate all these tips fairly easily into your current already pretty good serve.

After incorporating these, I think you THEN can go on to incorporating the big shoulder turn that will get you even more power.

But as you can see from the above sequence where Pete ends up with his back facing the court that this needs to start during the ball toss, and I think for most this harder to add in than the above, even though it should eventually be your goal.

Not bad.
I'd take more time between each serve, since you HAVE the time, to concentrate on storing up the energy, and then hit the ball. Don't just go thru the motions when you serve.
Maybe more sideways.

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I was very rushed between the serves only for the sake of the video size. I normally take a bit longer, although i sometimes rush between first and second serves.

The more sideways part, is something i will be looking into, thank you

I can pick up the ball in ALL the above ways or at least versions thereof, except "expert" way, which is impractical. I also pick up balls using just my foot (soccer method) But doing any of these, would slow me down in the video and make it longer

When Cheetah's advice is on picking up balls, you know you're doing something right

But in all seriousness, two things that stand out to me/you might want to try:

1. Turn your shoulders more when loading up to the trophy pose
2. If you crank it up, you may end up hitting yourself in the leg; f you're hitting a kick serve, follow through more to the right of your body, and if slice/flat, more to the left. Either way, you'll avoid your legs :wink:

That being said, I really like how fluid and easy it looks, and you seem to get a lot of power from it, not to mention that you seem to know where you want to place it. Very nice serve!

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hehe

1. hmm...will need to look into this - thanks
2. I tried to serve first serves more here...My kick/2nd serve is generally "better" or more consistent than my first. My first serves is not as good as I want it to be. Not to make any excuses, but the racket I'm serving with, does not feel great at point of contact. Too much flex and too little power - lead helps, but will be serving with new rackets in a month or so and also hopefully newer balls.

I'm not exactly sure what's going on, but your racquet seems to stop before it completes the arc that a follow through generally follows, and you slow the racquet down a lot here. You should have the mindset of keeping the racquet going and continuing through the swing, speeding through contact and not consciously slowing the racquet after you hit the ball

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Do you mean at the end of the follow through? Not sure where you mean. All i can think of, is that the pronation is causing me to kind of not flow through enough at the end of the serve possibly. (could be that I'm sub-consciously trying to recover after the serve) - not sure what it is though....but i agree that a serve should rather have one movement than jerky segmented ones.

The racket should be to your side, on the left, when you're finished with the swing. Right now, it's in front of you. That means you have to consciously slow down the swing in order to not hit yourself

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hmmm....it is hard for me to pronate AND end to the left. (i have actually a few years back hit myself on the shins twice in a row on exactly the same place lol - but this was before i even knew what pronation was)

see if you can incorporate more hip and torso rotation. but this would be a big change esp the stance.

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I have a problem though...even though I want to do what you are speaking of...lead with the hip like a bow, land on the left leg and whatnot...i kind of have a bad left knee (overuse aside from tennis or possible injury). In this vid, my leg and hip movement is not what it normally is or what i would like it to be...

It sometimes feels like i really land quite hard on the left foot...and even in my groundstrokes my split step is sometimes too hard.
I am actually trying to learn a less demanding technique on the knee without having to only use my arm, and without losing power. Not sure if thats possible...but compromise is...so somewhere I will need to compromise.

You have some good advice above already. But adding in the greater shoulder rotation will take a long time to get the timing down.

What I would recommend you working on first is the following:...

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But as you can see from the above sequence where Pete ends up with his back facing the court that this needs to start during the ball toss, and I think for most this harder to add in than the above, even though it should eventually be your goal.

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Thank you for a very intensive and valuable post. It makes sense, especially the shoulder part and not dropping the left arm too quick. On the legs part, I may have trouble physically with my bad knee....any tips on protecting my legs better? With the use of my legs and stomach muscles, i have learnt to protect my back. But now it seems, i did not protect my legs enough.

The pronation pic you posted, is quite valuable for someone I am trying to teach how to serve. I would expect however, a more stretched out wrist? Am i wrong? Or is it possibly different how woman do it these days?

Thank you for a very intensive and valuable post. It makes sense, especially the shoulder part and not dropping the left arm too quick. On the legs part, I may have trouble physically with my bad knee....any tips on protecting my legs better? With the use of my legs and stomach muscles, i have learnt to protect my back. But now it seems, i did not protect my legs enough.

The pronation pic you posted, is quite valuable for someone I am trying to teach how to serve. I would expect however, a more stretched out wrist? Am i wrong? Or is it possibly different how woman do it these days?

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The pronation pic is of a twist serve, so there is slightly less ulnar deviation at the wrist than a first serve.

I was surprised at how few pics I could find of male players taken from directly in front or behind at ball impact to show the angles at their wrist and elbow.
But here are two I found:

Murray serving:

Ferrero serving

You say you have a "bad knee". Is there osteoarthritis or some type of tendon/ligament problem? If not, you may find you can have stronger legs - to help protect the knee joint - from doing squats and deadlifts, even if the weight lifted is quite modest.

I have a problem though...even though I want to do what you are speaking of...lead with the hip like a bow, land on the left leg and whatnot...i kind of have a bad left knee (overuse aside from tennis or possible injury). In this vid, my leg and hip movement is not what it normally is or what i would like it to be...

It sometimes feels like i really land quite hard on the left foot...and even in my groundstrokes my split step is sometimes too hard.
I am actually trying to learn a less demanding technique on the knee without having to only use my arm, and without losing power. Not sure if thats possible...but compromise is...so somewhere I will need to compromise.

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no, actually in your video your jump is just about the same height as sampras in above photos. if your knees hurt currently serving, you don't really have to jump. keep your left foot on the ground and just kick back with your right leg for balance. It might give you more consistency actually. and the loss of power is not that much actually. if you try this your stance should be turned even more left. see how your left foot is pointing when landing. closer to there for your left foot.

I was surprised at how few pics I could find of male players taken from directly in front or behind at ball impact to show the angles at their wrist and elbow.
But here are two I found:

Murray serving:

Ferrero serving

You say you have a "bad knee". Is there osteoarthritis or some type of tendon/ligament problem? If not, you may find you can have stronger legs - to help protect the knee joint - from doing squats and deadlifts, even if the weight lifted is quite modest.

Click to expand...

Thanks for the video and great pics. I will try and post a vid of my second serve one day...but i never really thought or realised as much that a angled wrist works differently with different serves.

As for my knee...i would say its probably a little of everything you mentioned.
I once jumped and reached for a ball stuck in a fence, which made my knee more sensitive years back. But this may sound funny, but my car clutch combined with traffic, is placing too much strain on the knee. Combine it with this and that, and you sit with a overworked knee. I would not say i have weak legs in the sense that it needs muscle to protect it. But what is very strange is that my knee would very erratically "decide" for itsself it wants to be sore that day...not having done anything strange. My knee almost gets in a bad mood lol.

no, actually in your video your jump is just about the same height as sampras in above photos. if your knees hurt currently serving, you don't really have to jump. keep your left foot on the ground and just kick back with your right leg for balance. It might give you more consistency actually. and the loss of power is not that much actually. if you try this your stance should be turned even more left. see how your left foot is pointing when landing. closer to there for your left foot.

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I'm not very tall though. But maybe i should give this a try on bad days.

The following photo sequence by Toly clearly shows that to get the rapid spin on a kick serve, the ulnar deviation has to be occuring very rapidly while the ball is being struck, and the ball is rolling along the surface of the raqcuet.

To get that most rapid phase of ulnar deviation to produce the maximum amount of spin, the racquet has to strike the ball lower than on a flat serve, with the "brushing up" on the ball occurring as a result of that fast ulnar deviation.

If you read the original thread Toly cogently points out that it is ulnar deviation that is responsible for almost all the spin, not the action of the arm swinging (although some might counter that the ulnar deviation is largely a passive result of the heavy racqhet being being thrown up).

So in pic one below, he points out the arm is moving forward, while it is the ulnar deviation that is doing the brushing in pic 2:

On the other hand, in a first serve the ball is struck more in front of you, and by that time the ulnar deviation has largely occurred, with any residual ulnar deviation slower than during a kick serve.

As for my knee...i would say its probably a little of everything you mentioned.
I once jumped and reached for a ball stuck in a fence, which made my knee more sensitive years back. But this may sound funny, but my car clutch combined with traffic, is placing too much strain on the knee. Combine it with this and that, and you sit with a overworked knee. I would not say i have weak legs in the sense that it needs muscle to protect it. But what is very strange is that my knee would very erratically "decide" for itsself it wants to be sore that day...not having done anything strange. My knee almost gets in a bad mood lol.

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You really should get checked out and see what the problem is what that knee.
It may mean a big difference in whether you need to take some time off, or whether there is some strengthening regimen that could help you come back with less problems.

A worry is that articular cartilage does not contain pain sensors, so it isn't until the overlying joint space itself becomes inflammed that pain occurs.
And jumping and landing on that left knee, which you also pump the clutch with, could become a bigger problem if you continue the way you are.

CF, I know you're trying to help, but you really are making things so much more complicated and confusing than they need to be regarding the serving images. His serve is not that bad, and yes it could use some work, but showing four different players' serve sequences probably isn't the way to go about it when he's not going to become a pro.

Bad left knee.... no problem.
Stand much more back to target.
Pivot off your bad left leg and LAND on your good right leg.
BrianGottfried served like this, as did a few other guys, maybe Becker.
The pivot affect gives you twist power, so you don't need to jump as high, or not jump at all.
I find, at 63 now, I can serve full speed flat serves without jumping, around 100mph, because by not jumping, I can serve with more precision.
Don't jump. Instead, pivot and twist into your serves.

You really should get checked out and see what the problem is what that knee.
It may mean a big difference in whether you need to take some time off, or whether there is some strengthening regimen that could help you come back with less problems.

A worry is that articular cartilage does not contain pain sensors, so it isn't until the overlying joint space itself becomes inflammed that pain occurs.
And jumping and landing on that left knee, which you also pump the clutch with, could become a bigger problem if you continue the way you are.

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Hmmm....to be honest, i think traffic is the worst thing for my knee...the clutch stepping is too hard and regular. I am fine with groundstrokes. So this weekend, i specifically tried to serve less with my left leg....almost standing at times and a longer warmup. Earlier you guys advised me to lift my left shoulder more, and strangely enough, I had huge serves, almost faster than normal, even without my healthy knee.

Not to self diagnose or anything:
But the pain seems to be on the actual patella, or patella tendon....middle of knee. Not sure if its bone or tendon though (although it feels more like bone than tendon at times), but feels more on outer layers than the insides....http://www.ismoc.net/images/knee_rev.jpg

CF, I know you're trying to help, but you really are making things so much more complicated and confusing than they need to be regarding the serving images. His serve is not that bad, and yes it could use some work, but showing four different players' serve sequences probably isn't the way to go about it when he's not going to become a pro.

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I take some parts, and reject other parts...still interesting though.
Not planning to make drastic changes on my serves for now (my double backhand is priority)...but its good to know some technical things, even though i won't necc apply all of it.

Bad left knee.... no problem.
Stand much more back to target.
Pivot off your bad left leg and LAND on your good right leg.
BrianGottfried served like this, as did a few other guys, maybe Becker.
The pivot affect gives you twist power, so you don't need to jump as high, or not jump at all.
I find, at 63 now, I can serve full speed flat serves without jumping, around 100mph, because by not jumping, I can serve with more precision.
Don't jump. Instead, pivot and twist into your serves.

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My plan is to do what you speak, except not jump and land with the right knee. I plan to basically focus less on jumping with just the left leg. I think my forward motion put too much strain on the left leg, causing it to do most of the work when jumping (hard to see on the vid, but thinking back, i think it does most of the jump work). I need to either focus to jump with both legs to distribute the work, or jump less. Backward to forward rocking/momentum should naturally make me land on left foot, instead of trying to jump left and land left.

The *more* shoulder lift thing PSV and Charliefederer mentioned, definitely seems to have been an awesome tip - i had to toss the ball higher and had less disguise, but my power increased with less effort.

My plan is to do what you speak, except not jump and land with the right knee. I plan to basically focus less on jumping with just the left leg. I think my forward motion put too much strain on the left leg, causing it to do most of the work when jumping (hard to see on the vid, but thinking back, i think it does most of the jump work). I need to either focus to jump with both legs to distribute the work, or jump less. Backward to forward rocking/momentum should naturally make me land on left foot, instead of trying to jump left and land left.

The *more* shoulder lift thing PSV and Charliefederer mentioned, definitely seems to have been an awesome tip - i had to toss the ball higher and had less disguise, but my power increased with less effort.

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Pushing off with both legs is exactly what you optimally should be doing. (I'm just a bit worried with that knee though.)

With a deeper knee bend, and the with your tossing shoulder pointed straight up, it will seem that the ball is a lot further away than it used to be with your old motion as you look up at it.

But as you launch yourself up at the ball, you will really feel what Pat Dougherty, the Bollettieri Camp "Serve Doc" describes in hitting "up the mountain".
"Up the Mountain" excerpt form Serve Doctor presents: M.P.H. http://www.youtube.com/watch?v=WlPVdppfYGs

And you will need to learn to land in different way - on that left leg.
Leg Kick on Tennis Serve http://blip.tv/fuzzy-yellow-balls/leg-kick-on-tennis-serve-1190196
If your back (right) leg is kicking straight back, it means you are getting your weight moving into the court - if it is going to the side, you are not getting your weight moving first up and into the court.

But ...

You mentioned that your knee is already bothering you.

So if all this pushing off and jumping and landing is making you worse, you can still have an effective serve using your body, without a really big leg push off.

Pushing off with both legs is exactly what you optimally should be doing. (I'm just a bit worried with that knee though.)

With a deeper knee bend, and the with your tossing shoulder pointed straight up, it will seem that the ball is a lot further away than it used to be with your old motion as you look up at it.

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Yes i agree...i do however toss the ball higher in this instance, else my timing is off. A higher ball toss seems to give me better timing and power...flow motion...but what i really dislike, is that disguise harder to do with it and some opponents read these serves better. I suppose it wont matter if the serve is good enough though.

And you will need to learn to land in different way - on that left leg.
Leg Kick on Tennis Serve http://blip.tv/fuzzy-yellow-balls/leg-kick-on-tennis-serve-1190196
If your back (right) leg is kicking straight back, it means you are getting your weight moving into the court - if it is going to the side, you are not getting your weight moving first up and into the court.

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I think i need to arguably land closer to the baseline, and not as deep. Except maybe when i want to serve and volley.

But ...
You mentioned that your knee is already bothering you.

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What I don't understand about this knee, is that it comes and goes. To me that says something external is happening - like clutch or weather?

So if all this pushing off and jumping and landing is making you worse, you can still have an effective serve using your body, without a really big leg push off.

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Im not sure that its making it worse per say...it is however uncomfortable doing it.

When/if the knee is better, may be a better time to work on that big leg push off and left leg landing with the right leg kick back.

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Yes...for now, i will need to use a much less demanding serve and do as you say. It worked the past weekend....so it can only improve. When the knee is better, i can maybe use more legs, but who knows, by that time maybe it wont even be needed. The ball toss and shoulder thing really feels like a solution so far.
Thankfully i don't have much knee problems on the groundstrokes that i know of.

ps. That up the mountain serve "pitching concept" vid is quite good thanks. I learned something similar once from a coach, but totally forgot this concept and it is a good reminder.

The simpler version with the girl serving, makes a lot of sense...but seems like a drastic serve to learn...it would mean me moving from a platform serve, to a pinpoint serve.

The archer's bow is to help you angle your swing upwards, helping you jump upwards and into the court, adding swing speed to your racket.
Like a cartwheel, if you increase it's moment of action, you can increase it's axxis of rotation.

The archer's bow is to help you angle your swing upwards, helping you jump upwards and into the court, adding swing speed to your racket.
Like a cartwheel, if you increase it's moment of action, you can increase it's axxis of rotation.

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Well...the shoulder thing is definitely working for me so far (so thanks guys)....I am also considering to have my back foot slightly further angled, but not sure if thats a good idea. I just cant get my head around the pronation thing without "almost hitting myself" - it makes sense that I should eventually end with my racket around my body, which I don't.

ps. New rackets also helping my serve - will try and update the vid sometime using them instead.

Some coaches have been advocating the application of a ready position at the end of the service motion, since modern tennis allows the returner to get the ball back much faster than the old daze.
You end your motion in a relaxed, non ready position with arm dangling by your sides and feet together.
Swing faster.

Some coaches have been advocating the application of a ready position at the end of the service motion, since modern tennis allows the returner to get the ball back much faster than the old daze.
You end your motion in a relaxed, non ready position with arm dangling by your sides and feet together.
Swing faster.

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I think in match situation i recover to a better ready position.
Funny....It is only with the slice out wide that my racket goes around my body a little more.

mikereller: I'd like to see a little more body turn. I'm not saying start out like Johnny Mac with your back to your opponent but just a little more body turn might gain you a few MPHs.

Well...for one thing, the more extreme stance didn't do it for me...so that won't work. I will need to work more on the shoulders as you say.

As for eventually ending around my body without hitting myself, I will have to work that out. Maybe I have to pronate less for this to be possible.
(there is a lot of momentum on my pronation which throws the racket out sideways away from the body, instead of around it)

I think in match situation i recover to a better ready position.
Funny....It is only with the slice out wide that my racket goes around my body a little more.

and

Well...for one thing, the more extreme stance didn't do it for me...so that won't work. I will need to work more on the shoulders as you say.

As for eventually ending around my body without hitting myself, I will have to work that out. Maybe I have to pronate less for this to be possible.
(there is a lot of momentum on my pronation which throws the racket out sideways away from the body, instead of around it)

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You can try keeping your stance the same but turning your body a little more so that you uncoil into the serve.

Exactly what I mentioned.
Keep your feet stance, turn your shoulders closed a little more.
Currently, you are almost twisting forwards to FACE your target, so you don't get the rotation into the swing.

As far as using your legs serving, a big jump isn't necessary. Here is a vid of me serving - both my legs are pretty weak from injury.http://youtu.be/3fgCvFjxVLM
If you can find a good video of Michael Stich's serve, it is pretty similar in the small knee bend. The back leg comes through with the hip rotation. An old-school style.
There's some McEnroe-ish serves just past 5:00. Maybe give that a try, at least for getting some practice getting some hip rotation. Lots of good video with his serve on youtube.

As far as using your legs serving, a big jump isn't necessary. Here is a vid of me serving - both my legs are pretty weak from injury.http://youtu.be/3fgCvFjxVLM
If you can find a good video of Michael Stich's serve, it is pretty similar in the small knee bend. The back leg comes through with the hip rotation. An old-school style.
There's some McEnroe-ish serves just past 5:00. Maybe give that a try, at least for getting some practice getting some hip rotation. Lots of good video with his serve on youtube.

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I generally like your serve. You seem like a tough player. You probably beat many younger kids?

Yes, jumping does have advantages on the serve in terms of the angles you get into the court. I'm not necessarily against it except that it can make the serve motion inconsistent and ends up being a net negative. In terms of ball speed, however, its contribution is small. Think of how long it would take you to hop to the other side of the court with that motion.
No question that Brian Battistone's jump helps his serve. It is really impressive to see in person.http://www.youtube.com/watch?v=CQYOW1DlydU

My serve has changed since I uploaded this video...I am surprised how much some of the tips here by members helped me to improve. The toss-up is so so important imo...
I also serve better with the BLX Surge...

After watching some AO this year, I just realised how much faster the pro's serve (even the women). Is there a way to work out ones speed by comparing similar videos? Or any guesses what the speed of my serve could be? My guess is that the fastest one is probably around 100mph if I'm lucky? (I serve faster now especially with new balls and a stiffer racket - need to create a new video of what my serve is like a year later)

1) You need a camera that videos at 30 or 60 fps. DSLR's with 60 fps and fast shutter speeds in video mode are ideal. Smartphone cameras probably have 30 fps in good lighting but in lower lighting many slow down the frame rate. ?? You have to verify the frame rate of smartphone cameras (see the end).

2) Estimate the trajectory of the ball and place the camera to view from the side, squarely perpendicular to the ball's trajectory. (Small angular errors from perpendicular when placing the camera or between serves decrease slightly the indicated ball speed.)

3) Measure the ball travel distance between two frames.

100 MPH is 1760 inches/sec

1760 "/sec / 30 fps = 58.6 "

If a ball travels 59" for a 30 fps camera the speed is 100 MPH. If a ball travels 29.3 inches between frames for a 60 fps camera the speed is 100 MPH.
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Distance = Velocity X time

V = D x 60 at 60 fps
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Do in bright sunlight so that the camera's automatic exposure control will select a fast shutter speed and the ball will have less motion blur. It's OK if the ball is blurred, just estimate position of the blur center or leading edge, etc.

For wide angle lenses the magnification will vary across the frame. For calibration, video a scale of known length held in the direction of the ball's trajectory. In a pinch your racket will do for a calibration scale. Walk it across along the direction of the ball's trajectory. To minimize magnification variation across the frame it is probably best to use a wide angle setting for small motion blur and have the camera some distance from the trajectory, so that you only use the middle 25% of the frame to make your two measurements - two ball locations, one on a frame and the other on the next frame. Place a piece of paper on the camera or computer screen and mark the ball locations for each frame. Best if the camera is held stationary.

Smartphone Frame Rate Verification. For smartphone cameras first assume the frame rate is 30 fps, it most likely is 30 fps and accurate. Measure some serves. Later, verify the frame rate - toss or bounce the ball and video the peak of the bounce when the ball stops and starts to drop. Video also a scale or your racket length. Using a calculation for gravity I can tell you if the camera was 30 fps, 60 fps or at an off speed such as 24 fps.

DON'T use a smartphone indoors for this measurement unless your verify the frame rate in that lighting.